1. Field of the Invention
The present invention relates to an intraluminal magnetic resonance imaging (MRI) probe which may be used for intraluminal MRI. The present invention is sized sufficiently small to be inserted into a patient intraluminally. The probe of the present invention comprises a substrate having a dielectric constant in the range of 1-1000, and first and second conducting layers on each side of the dielectric. The present invention is configured to result in a distributed capacitance.
2. Description of the Prior Art
Prior art MRI probes exist in a variety of geometrical configurations. U.S. Pat. No. 5,699,801 to Atalar (Athe>801 Patent≅) discloses an MRI probe having pair of electrodes arranged in a parallel configuration and embedded within a dielectric material. FIG. 8 of the >801 Patent discloses a probe embodiment comprising two pairs of electrodes extending through a dielectric material and positioned in planes oriented at 90 degrees relative to each other.
U.S. Pat. No. 4,672,972 to Berke (Athe>972 Patent≅) discloses an NMR probe embedded within a probe head region disposed at the distal end of a catheter/endoscope. FIG. 4 of the >972 Patent discloses an integrated circuit probe for converting the detected NMR spectra into an electrical signal having a frequency fS.
U.S. Pat. No. 6,171,240 to Young et al. (Athe>240 Patent≅) discloses a radio frequency (ARF≅) probe adapted for use in MRI comprising a loop of an elongated electrical conductor arranged to form a twisted wire pair and a means for operating the probe in a transmit and receive mode for intraluminal MRI.
It is desirable have a RF probe that is small enough for intraluminal insertion, in which has a confined electric field due to distributed capacitance. The use of distributed capacitance will eliminate losses due to electric field lines penetrating the body and inducing eddy currents. Such a design will be less sensitive to flowing blood, which is normally encountered in intraluminal applications. A distributed capacitance design will also result in an RF probe that has a higher signal to noise ratio and a higher quality factor than is available with nondistributed capacitance. The term Aquality factor,≅ as used herein, is defined as the ratio of energy stored to energy loss in the resonator during one RF cycle. The present invention provides an RF probe for intraluminal MRI that is small enough for intraluminal applications and which has a distributed capacitance.